Multipotent cells are known to be useful in various medical procedures to assist in the healing of an affected area of a patient, for example by providing enhanced cellular regeneration of a treatment site. The multipotent cells can be sourced from various tissues of the body of a living being for use in a surgical procedure. The multipotent cells may be autologous, where the patient is the donor for the cells that are used to treat the same patient. The term “multipotent cells” includes adipose-derived stem cells, which have also been described as adipose-derived stem/stromal cells, adipose-derived adult stem cells, adipose-derived adult stromal cells, adipose-derived stromal cells, adipose stromal cells, adipose mesenchymal stem cells, lipoblast, pericyte, preadipocyte, and processed lipoaspirate cells.
It is well known that adipose tissue in the human body contains significant numbers of multipotent cells, in fact, far more multipotent cells are stored per unit volume in fat than in bone marrow. Some estimates give factors of 500:1 for the ratio of multipotent cells stored per unit volume in adipose tissue relative to those stored in bone marrow.
In order to retrieve the multipotent cells from fat, a sample of fat is retrieved from the patient by techniques known in the art, generally, for example, surgery or liposuction. It has been known to utilize enzymes, such as collagenase, or trypsin, etc., to breakdown peptide bonds in the collagen network holding the adipose tissue together, and to break down the basement membrane around the individual cells. Once this has been done, the multipotent cells may be separated out, and concentrated using centrifuge, sedimentation or filtration techniques, and the concentrate is washed to remove the enzyme (residuals) used to treat the fat sample. It is thought to be vital to remove the agents that had been added to break down the collagen network, as these enzymes are thought to cause reduced viability of the harvested cells. The washed concentrate is then available for injection back into the patient, for the purpose of accelerated repair of an injury. Unfortunately, this process to prepare a useful sample of multipotent cells, takes several hours (and in some cases up to 14 days), that makes the ad-hoc use of such a procedure difficult or impossible, required multiple processing steps, thereby increasing the potential for contamination, compromised sterility, and the process demands skilled technical knowledge.
It is previously known that in addition to preparing samples of multipotent cells isolated from adipose tissue, the multipotent cells could be isolated from a sample of bone marrow. However, in order to retrieve cells from bone marrow, the patient has to endure a very uncomfortable puncture of the marrow spaces/cavities in bone (e.g., the iliac crest) before bone marrow aspirate (BMA) is drawn. The BMA sample is then spun down in a centrifuge to gain a cellular concentrate that can then be injected into the patient for the repair of some injury. Although the timing of this procedure permits the ad-hoc use in an operatory, the concentrate obtained may have an insufficient dose level for some applications without adopting a culturing method to increase the concentration. The procedure utilizing BMA may be competitive to procedures using multipotent cells from fat, however, the harvesting of tissue for BMA procedures has the disadvantage of requiring a painful access procedure.
Accordingly, a need exists for a rapid multipotent cell collection, isolation and concentration apparatus and procedure that enables the ad-hoc use of harvested cells in a surgical procedure, where the harvested cells can be prepared in a short timeframe (less than 5 minutes), and capable of being performed following a simple protocol with easy steps that do not require extensive technical training. The subject invention addresses that need (and others) by providing a compact, sterile, self-contained, easy-to-use centrifugal separation unit to provide quick and reliable multipotent cell isolation from collected or harvested fatty tissue and methods for quickly and reliably isolating multipotent cells from collected or harvested fatty tissue. The fatty tissue can be collected or harvested by any means known in the art, including, but not limited to, liposuction and surgically harvested fat. In the case of adipose tissue, the biologic mixture consists of the fatty and fibrous tissue, plus a portion of the tumescent fluids used to stabilize the fat for extraction (e.g., saline, epinephrine, lidocaine, etc.), with the multipotent cells residing in the fatty and fibrous tissue. To isolate the multipotent cells for harvesting, the device mechanically breaks down the collagen structure, and separates its fractions by specific gravity, in order to isolate the fraction containing the multipotent cells for collection and use in various types of procedures, be they diagnostic, therapeutic, or surgical.
With regard to fat processing for reimplantation, one may alternatively obtain a sample of harvested fat to be utilized surgically, in a manner that does not require separating out the multipotent stem cells from the tissue structure, as described immediately above. Fat transfer, for example, also referred to as autologous fat grafting, involves the removal and re-implantation of a patient's adipose tissue. The adipose material is typically removed from areas of the body like the abdomen, thighs, or buttocks. Depending on the extraction technique (e.g., surgical removal, liposuction, etc.), it may be necessary to remove the certain portions of the harvested sample (e.g., tumescent solution) from the tissue extract. It may further be necessary, depending on the techniques used to harvest the sample, to size the tissue, in order to create a homogenous product and present a material with appropriate particulate sizes for the purpose intended. Sizing of the tissue is desirable in many clinical applications where there is limited access for re-implanting the sample. For example, where there are aesthetic concerns (e.g., facial cosmetic procedures), in order to minimize scarring from incisions, the procedure may be performed by injecting the material via a small diameter needle. When used as a facial filler, fat grafting can improve the creased and sunken areas of the face, and add fullness to the lips and cheeks. Fat grafting is also commonly used in breast and buttocks augmentation, usually in place of implants.
Current fat grafting is performed by harvesting the adipose material, using a variety of techniques and surgical tools. Consequently, the product that is harvested may be quite different in cell viability, texture (e.g., particle size) and composition (e.g., fatty tissue, blood, tumescent solution, oil, saline, water), as a result of the technique utilized for harvesting. This results in variability in the material that may beneficially be accounted for during the processing of the fat sample prior to re-implantation. Furthermore, the preparation techniques and instruments applied to the fat sample for re-implantation may also vary, potentially resulting in a product prepared for re-implanting that may be sized to a particle size that is too small for the intended use of the material, resulting lower cellular viability attributable to the excessive processing, increasing the potential for washout of the implanted material and/or volume loss in the implanted site. Alternatively, a sample that is sized to particle size that is too large for the intended use may result in challenges upon implantation, such as uneven texture, blockages of the narrow gauge needles utilized for re-implantation, and difficulty in the revascularization of the large particle size graft which may negatively affect viability.
What is needed is a device that is able to size the material to a useful consistency, and is able to provide a reliable composition of the material for implantation, regardless of the original collection technique, in order to avoid the above mentioned problems.
What is needed further needed is a unitary device that can quickly process, in a sterile, closed system, the fat harvested for fat grafting, into a homogenous material, having a reliably uniform particle size. The ideal device would consistently size the material in a manner that is independent of the manner of initial harvesting of the fat sample. Additionally, what is needed is a device capable of removing at least a substantial portion of unwanted components from the harvested sample, and preserving the components to be implanted, such as by removing from the sample one or more of: blood, water, saline, oil, tumescent solution. Additionally, the ideal device would minimize the potential for damage to the cellular components and tissue structure within the sample, in order to maximize the viability of cells to be implanted.